The present invention relates to a device for the transfer of information between electric components or circuits, for instance LSI-circuits, on a substrate by utilizing a directive or directivable narrow spectrum radiation, for instance laser radiation.
The problem of the present invention is to simplify the prior art optics communication technique into a technique which is more simple and flexible than the prior art ones and, additionally, which is competitive from a cost point of view.
It is known to use a light of narrow spectrum or coherent light from a laser as an information carrier between electric circuits on a substrate. IBM Technical Disclosure Bulletin, Vol. 22, No. 8B, January 1980 for instance describes a system where optical light conductors are used for such light between two circuits.
However, very surprisingly, according to the present invention it has been found that such light has a considerably broader field of application. It has been found that, basically, there is no need to use a compulsory encasement in a light conduit, i.e. an optical fibre, instead the light may propagate freely within the substrate under certain conditions.
Thus, the invention provides a device for information transferring communication between components or circuits on a substrate by using directive, narrow spectrum radiation, for instance laser light, as an information transferring medium.
The device is characterized in that the substrate is formed from a material that is transparent for such radiation, that the components are placed in predetermined positions, at least partially within the transparent material, that the components in areas thereof lying inside said material are provided with input and output elements responsive to said radiation, and that said elements due to the location of said components are arranged to communicate by means of said radiation directly through the material of the substrate without reflection at the surfaces of the substrate.
In order to eliminate stray illumination inside the substrate and undesired reflection of radiation in the narrow edge sides of the substrate, the non-active portions thereof are covered or coated by a material that prevents or highly attenuates reflection of radiation, for instance painted dark.
In order to prevent an undesired interference between radiation inside the substrate, said input and output elements are placed such that parallel, co-existent rays of radiation are eliminated. As there are involved relatively short propagation distances; normally the substrate has a dimension not larger than A4-shape, the input and output elements may be packed relatively tight without any risk for said parallel co-existence.
Today there is available a well developed mechanic microtechnique which allows an accurate definition of position. The electrochemical and photografic semiconductor technique does also allow a very exact positioning of components and component parts of an electric circuit.
In one embodiment of the present invention such components are placed in well defined recesses in a broad side of a substrate, and at least someone of the narrow edge sides of the substrate has means for receiving or transmitting radiation from said output and input elements, respectively.
In order to provide a current supply to the electric circuits on the substrate the arrangement preferably is such that both broad sides of the substrate have external conductive surfaces which are electrically connectable to said components.
In order to further improve the flexibility, the input and output elements of the components or circuits are connected to a programmable arrangement of connection paths between elements of a respective component or circuit.